Escapement timing mechanism



United States Patent Inventor Abraham L. Korr 8712 Hickory Drive, Philadelphia, Pennsylvania 15340 Appl. No. 767,740

Filed Oct. 15, 1968 Patented Nov. 10, 1970 ESCAPEMENT TIMING MECHANISM 7 Claims, 3 Drawing Figs.

US. Cl

102/71, 58/1 17 Int. Cl F42c 9/02, G04b 15/14 Field of Search 102/83, 84,

[56] References Cited UNITED STATES PATENTS 1,368,004 2/1921 Watson etal. 58/123 2,453,479 11/1948 Whitehead 102/84 Primary ExaminerBenjamin A. Borchelt Assistant Examiner-Jerald J. Devitt Attorney-Harry M. Saragovitz, Edward J. Kelly, Herbert Berl and S. Dubroff ABSTRACT: An escapement wheel, connected with a timing shaft powered to rotate in one direction, is confined to stepby-step rotational movement by an escapement or pallet lever pivoted to move through a small angle on either side of the spin axis of a projectile in flight. The lever is tubular and contains a ball of resilient material which bounces between cushioned end plates therein along the axis to provide the oscillating movement thereof and thereby replacing the usual escapement spring.

Patented Nov. 10, 1970 3,538,851

-W ATTORNEYS- ESCAPEMENT TIMING MECHANISM The invention described herein may be manufactured, used and licensed by or for the Government for governmental purposes without'the payment to me of any royalty thereon.

The present invention relates to escapement timing mechanisms which are adapted for use in projectiles and like spin-type carriers to time the operation of fuzes and like detonating elements therein.

In the past, escapement mechanisms used in watches and time fuzes for example, have used escapement wheels or levers wherein the restoring force of a displaced lever or wheel was obtained by tension applied to an escapement spring. Since the escapement spring in a normal watch mechanism is usually of the coiled type and that in a mechanical time fuze is a flat spring type, such escapement mechanisms have often failed because of their inability to survive severe environments of shock and vibration.

It is an object of this invention to provide an improved escapement timing mechanism which eliminates the use of any escapement spring and provide a structure that is adapted to survive severe environments of shock and vibration such as found in the firing of projectiles and like spin-type carriers. Thus by eliminating the spring elements in the escapement, sensitivity to spin and vibration are thereby eliminated as well.

In a preferred embodiment of the invention, a pivoted escapement or pallet lever is associated with a pallet or escapement wheel having a toothed periphery cooperating with a pair of spaced pallet blades carried by the pallet lever for moving the escapement wheel in step-by-step rotation under the power ofa driving spring.

The escapement or pallet lever is in the form of a cylinder with two adjustable end plugs or caps screwed threaded therein. The cylinder is pivoted about its center and is aligned with the spin axis of the carrier projectile or missile on its longitudinal axis. Contained within the cylinder is a resilient ball which bounces between the ends of the cylinder to provide the oscillating force for the lever. The resilience of the ball is aided by the ball striking a spring mounted striker plate at each end of the cylinder as it moves to rebound in the opposite direction. Added centrifugal force is applied each time the ball crosses the spin axis near the end of its travel in either direction.

When the cylinder or lever begins to oscillate about its pivot point because of setback forces and spin, the ball oscillates within the cylinder due to its resiliency and the restoring force of the piston and the driving spring from the pallet wheel.

This, in turn, enables the cylinder or lever to continue oscillating with the aid of the power supplied by the escapement wheel from the driving spring.

The advantages of this system is not as sensitive to spin as the usual spring movement and it is more rugged and stable, and also is more effective in nongravitational environments as found in projectiles in flight.

The invention will further be understood from the following description when considered with reference to the accompanying drawing, and its scope is pointed out in the appended claims.

In the drawing,

FIG. I is a view, in elevation, of a spin-type carrier such as an artillery projectile provided with an escapement timing mechanism embodying the invention,

FIG. 2 is a plan view, in cross section, of the escapement timing mechanism of FIG. I, on a larger scale and in detail, for operation in accordance with the invention, and

FIG. 3 is a similar cross-sectional view, in elevation, of the timing mechanism of FIG. 2 showing further details thereof in accordance with the invention, and with its use in a timing system schematically indicated.

Referring to the drawing, wherein like parts throughout the various figures are indicated by like reference characters, and referring more particularly to FIG. 1, a projectile or spin-type carrier 5 of the elongated cylindrical type is provided with an internal time fuze 6 which determines the firing time of the projectile. The fuze contains a timing mechanism which includes an escapement lever 7 which is oriented to lie along the longitudinal spin axis S of the projectile and is pivoted to oscillate on a transverse pivot axis P which passes through the spin axis at a right angle thereto. The spin of the projectile in flight may be imparted thereto by suitable rifling in a gun or like launching means by which it is fired, as is well known.

Referring now to FIGS. 2 and 3, along with FIG. I, the escapement or pallet lever 7 is of tubular or cylindrical construction having screw-threaded open ends and being symmetrical about a center or longitudinal axis C. The escapement lever or pallet lever is mounted in the projectile to lie normally along the spin axis S and is pivoted to move through a relatively small angle with respect thereto as indicated at A in FIG. 3 from a normal or mid position along the spin axis.

The escapement lever 7 is pivoted midway between its ends on the pivot axis P by means of a pair of radial pivot pins 8 which are located diametrically opposite to each other and secured to the tubular escapement lever, as indicated more clearly in FIG. 2. The pivot pins 8 are provided with suitable end bearings or bearing elements 9 located on opposite sides of the escapement lever 7 also as shown more clearly in FIG. 2. Thus, on the pivot axis F, the escapement lever is positioned to freely oscillate through the short angle A on either side of the spin axis, as indicated in FIG. 3.

A pair of escapement pallet blades 10 and 11 extend radially from and arecarried by the pallet lever and are equally spaced from the pivot axis P thereof in a plane normal thereto. Theseare arranged to cooperate with a peripherially toothed pallet or escapement wheel 12 mounted to rotate in the plane of the pallet or escapement lever 7 in close spaced tangential relation to said lever, as indicated in FIG. 3.

A timing shaft 15 is connected with the pallet or escapement wheel 12 for controlled rotation therewith. In the present example, as indicated in FIG. 3, the escapement wheel 12 is mounted directly on the shaft 15 and to rotate therewith. The timing shaft is the controlled output element of the timing system provided by the escapement mechanism and moves in a step-by-step rotational movement in one direction under control of the pallet lever 7 and the pallet elements 10 and 11. The shaft 15 is extended as indicated schematically by the dotted line I6 into driving connection with a time-controlled device such as a time-measuring device, a timer or counter, and is powered to move in the direction of the arrow of the pallet wheel 12 by a power or drive spring I8 for the pallet or escapement wheel.

The spring is mounted on the timing shaft and connected to drive the wheel in one direction, which in the present example is that indicated by the arrow above referred to on the escapement wheel 12. The escapement mechanism shown is provided with the usual tapered pallet or escapement teeth on the pallet wheel for applying the required slight driving force to the escapement lever 7 from the driving spring or power source 18. In the present example the pallet element 10 is shown in engagement with one of the teeth 20 of the pallet wheel 12, and due to the caming action between them, the pallet blade I0 is driven upwardly by the wheel tooth 12 to move the escapement lever 7 and the center line C thereof through the spin axis 8 over to the alternate position indicated by and along the center line position C2. When this occurs the pallet blade 11 then comes into engagement with the next driving tooth 21 of the pallet wheel 12 which, due to its caming action and the unidirectional movement of the pallet wheel 12, causes the pallet 11 to be driven upwardly with the pallet lever and back to the position shown in the drawing along the center line position C, as shown, with respect to the spin axis.

Oscillation control of the pallet or escapement lever 7 in this manner for timing purposes, is provided in the present mechanism by a longitudinally movable resilient hollow ball or timing element 22 which is free to move along the centerline or longitudinal axis of the escapement lever from end to end, and replaces the usual escapement spring found in other timing mechanisms of the escapement type. The hollow ball 22 fits loosely in the bore of the hollow tubular escapement lever and is made of thin resilient metal such as phospher bronze or stainless steel, giving it resilience or bounce.

At opposite ends of its travel along the bore of the tubular lever is the ball met by resilient rebound or striker elements. These are resilient spring-mounted pistonlike rebound platforms or striker plates 24 and 25 in each end of the tubular escapement lever. These plates are freely movable with a loose sliding fit within the bore of the escapement lever and are resiliently supported each by a short helical coiled rebound or supporting spring 26. The springs are each attached to the associated plate at one end and extending along the axis of the lever each into connection with a longitudinally-movable timing adjustment plug or end cap 27 for the escapement lever.

The adjustment plugs 27 and the rebound platforms or striker plates 24 and 25 are connected together by the rebound or supporting springs 26 so that the plugs 27 may be rotated to adjust the position of the plates 24 and 25 with respect to the center of the escapement lever or the pivotal axis P, thereby to determine the active length of travel of the ball 22 between the plates 24 and 25 and the timing operation of the mechanism. For this purpose the plugs 27 are screwthreaded into the ends of the escapement lever and provided with suitable screwdrive adjusting slots as indicated at 28.

Thus it will be seen that in operation, the ball 22 bounces between platforms or striker plates 24 and 25, each of which rccoils slightly against the rebound of springs 26 to add to the driving force of the resilience of the ball on its rebound or return trip across the length of the tube or lever to the opposite end. Thus when the escapement cylinder or lever begins to oscillate about the axis P by the application of an external force such as the setback force and spin in firing the projectile, the ball 22 is accelerated toward the resilient platform or striker plate 25, aided by the caming action of the escapement wheel blade 20 against the pallet blade under the turning force of the drive spring 18.

A basic function for the-springs 26 is to apply an initial movement or acceleration to ball 22 after the projectile has been fired. When the projectile is fired, setback forces the ball 22 back to the rear position against the plate 24. This also compresses spring 26 due to the setback action on the plate 24. Upon leaving the barrel, the spring 26 accelerates the ball forward so that together with the spring the ball, initiates oscillation ofthe pallet lever. Therefore the spring 26 has two functions, the one described and the initiation of the pallet lever oscillation after the projectile leaves the barrel of the gun. Thus another feature of value that this escapement has is that it can and does function immediately upon leaving the barrel, while present known escapement mechanisms do not function until an appreciable distance from the muzzle.

With the timing plugs or caps 27 properly adjusted with respect to the pivot axis P as the projectile spins about the spin axis S, additional energy is transferred to the ball 22 by the centrifugal action of the shell on the ball as it passes through the axis of spin S on each excursion of the lever 7 through the angle A with respect thereto, since the cylindrical or tubular escapement lever is centrally mounted for a normal position extending through the spin axis. By the resilience of the ball 22 and the restoring force of the rebound or supporting springs 26 through the platforms 24 and 25, the second cycle of the oscillating pallet lever is initiated as it is driven from the position occupying the centerline C2 and returns to the position shown in the drawing in FIG. 3. The oscillation thus continues with the aid of the power applied to the cylinder by way of the engagement of the pallet blades and pallet wheel and timed by the oscillation of the ball back and forth between the rebound platforms at the end of the pallet lever 7. The system thus operates with the pallet wheel 12 moving unidirectionally with the torque or driving force transmitted to it by the power spring or driving element 18, and as it moves it controls the timing operation of the timer or controlled device 17. As is known, this may be used'for various purposes as, for example, firing the projectile.

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It will thus be seen that the escapement mechanism of the present invention is most effective in a nongravitation system as would be found in the environment ofa projectile in flight. However it has other uses but has the advantage that it can operate directly offcenter a slight degree from the spin axis and may derive additional benefits in the timing operation of the pallet lever as has been described and as indicated in FIG. 3 for example.

From the foregoing description it will be seen furthermore that an improved escapement timing mechanism in accordance with the invention provides a simple construction adapted for low cost-manufacture and low-maintenance cost in operation. The cylindrical escapement lever is pivoted with its center lineor longitudinal axis on line with the spin axis of the carrier, projectile or missile, and the pivot axis is symmetrically positioned with respect to the pallet means provided thereon in contact with the escapement wheel. Within the escapement lever, the resilient ball is caused to oscillate back and forth and to cause the lever likewise to oscillate about its pivot point due to the resiliency of the ball and the restoring force of the spring-mounted pistonlike rebound platforms or striker plates at the ends of the lever. This, in turn, enables the cylindrical escapement lever to continue oscillating with the aid of the power supplied by the escapement wheel and driving spring therefore.

The advantages of this system are that it is not as sensitive to spin as the usual spring-controlled escapement means, it is more rugged and stable, and most effective in carriers of the spin type such as projectiles and the like.

lclaim:

1. An escapement timing mechanism comprising in combination:

a pivoted tubular escapement lever;

means providing a transverse pivot axis therefor intermediate between the ends thereof;

a pair of escapement pallet blades extending radially from and carried by the escapement lever and equally spaced from the pivot axis thereofin a plane normal thereto;

a peripherially-toothed escapement wheel mounted to rotate in the plane of the escapement lever in close spaced tangential relation thereto for engagement by and operation with said pallet blades;

a timing shaft connected with said escapement wheel for controlled rotation therewith;

means for applying a driving force to said timing shaft for rotation thereof and said escapement wheel in one direction;

a timed-controlled device connected with said timing shaft for operation thereby in response to a predetermined number of oscillations of said escapement lever;

21 longitudinally-movable resilient ball timing element in said tubular escapement lever freely movable along the axis thereof between the ends;

a resilient spring-mounted rebound striker plate positioned in each end of said escapement lever;

a coiled supporting spring connected with each of said striker plates for resiliently holding said plates in position to receive the impact of said ball element at each end of its travel through said escapement lever; and

a longitudinally-movable timing adjustment plug in each end of said escapement lever and connected each with one of said springs to hold and move each of said striker plates with respect to the pivot axis of said lever, thereby to control the timing action of said mechanism.

2. An escapement timing mechanism for a spin-type projectile, comprising in combination:

an elongated tubular escapement lever pivoted to oscillate through the axis of spin of the projectile on a transverse pivot axis intermediate between the ends of said lever and intersecting said spin axis at a right angle thereto;

a pair of escapement pallet blades extending radially from and carried by the escapement lever and equally spaced from the pivot axis thereofin a plane normal thereto;

a peripherially toothed escapement wheel mounted to rotate in one direction in the plane of the escapement lever in close spaced relation thereto for engagement and step-by-step control by said pallet blades as the escapement lever oscillates;

a timer device for said projectile having a timing shaft con nected with said escapement wheel for controlled rotation therewith and operation of said device at the end ofa predetermined rotational movement thereof;

spring driving means connected with said shaft for applying a driving force thereto for rotation with said escapement wheel in said one direction;

a hollow resilient ball mounted in said tubular escapement lever and freely movable along the longitudinal axis between the ends thereof;

a movable pistonlike rebound plate positioned in each end of said tubular escapement lever;

a helical coiled rebound spring connected with each of said plates for resiliently holding said plates in position to receive the impact of said resilient ball at the ends of its travel through said escapement lever;

a rotatable screw-threaded timing adjustment plug in each end of said escapement lever for limited adjustment along axis of said lever; and

said plugs being connected each with one of said springs to move and hold said stiker plates resiliently in position with respect to the pivot axis of said lever, thereby to control travel of said ball and timing action of said mechanism.

3. An escapement timing mechanism as defined in claim 2, wherein the tubular escapement lever is of plastic material and the ball is of relatively then metal for high resilience.

4. An escapement timing mechanism as defined in claim 2, wherein the resilient ball is of relatively-thin phosphor-bronz material.

5. An escapement timing mechanism as defined in claim 2, wherein the resilient ball is of relatively-thin stainless steel.

6. The combination with a cylindrical projectile casing having a longitudinal spin axis about which it rotates in flight, ofa time fuze therefor having a cylindrical housing mounted within said casing on said spin axis and an escapement timing mechanism therein, a timing escapement lever for said mechanism of cylindrical tubular construction mounted to lie normally along and coaxial with the spin axis and pivoted on a transverse axis intermediate between its ends to oscillate through a relatively-small angle equally on either side of said spin axis, a pair of spaced pallet blades extending radially from and carried by said escapement lever on opposite sides of said transverse pivot axis, a peripherally-toothed escapement wheel mounted to rotate adjacent to and in the plane of the said lever for alternate step-by-step contact with said pallet blades as the lever oscillates, a timing shaft connecte to rotate with said escapement wheel, means for driving said shaft end wheel in one direction against the stepping control of said pallet blades, a resilient ball timing element loosely mounted in said tubular escapement lever to freely move from end to end thereof and apply an oscillatory drawing force to said lever, and a resiliently-mounted pistonlike rebound plate positioned for meeting the throw of said ball element at each end of said lever, thereby to sustain and enhance the oscillatory timing movement of the ball element and escapement lever.

7. An escapement timing mechanism for a spin-type projectile, comprising in combination:

a tubular escapement lever pivoted to oscillate through the axis of spin of the projectile on a transverse pivot axis substantially midway between the ends of said lever;

a pair of escapement pallet blades extending radially from and carried by the escapement lever and equally spaced from said pivot axis;

a toothed escapement wheel mounted to rotate in one direction for engagement and step-by-step control by said pallet blades as theescapement lever oscillates; a timer device for said pro ectile having a timing shaft connected with said escapement wheel for controlled rota tion therewith and operation of said device at the end of a predetermined rotational movement thereof;

driving means connected with said shaft for applying a driving force thereto for rotation with said escapement wheel in said one direction;

a resilient ball mounted in said tubular escapement lever and freely movable along the longitudinal axis between the ends thereof;

a movable pistonlike rebound plate positioned in each end of said tubular escapement lever; and

an adjustable helical coiled rebound spring connected with each of said plates at each end of said lever for resiliently holding said plates in position to receive the impact of said resilient ball at the ends of its travel through said lever. 

